The application of LiFSI in lithium ion battery

 LiFSI is a lithium-ion battery electrolyte lithium salt with wide application prospects and has extremely high application value in the fields of lithium-ion batteries and supercapacitors. This aticle will introduce the application of LiFSI in lithium ion battery. 

Each new type of electrolyte lithium salt has its unique performance, which will bring many disadvantages when applied to lithium-ion batteries alone, and LiFSI is no exception. Therefore, the researchers integrated its performance with other lithium salts and played a synergistic role to improve the overall performance of lithium-ion batteries.

A research team ^[1] prepared an electrode solution by dissolving LiFSI in an organic solvent of ethylene carbonate / dimethyl carbonate / diethyl carbonate (mass ratio of 1: 1: 1: 1). And they have proved through experiments that the electrolyte added with LiFSI additive has higher conductivity and lithium ion migration number compared with ordinary electrolyte, At the same time, lithium-ion batteries using this electrolyte also show better cycle performance and rate performance.

Professor H.F. Xiang and his team^[2] prepared a totally nonflammable phosphate-based electrolyte composed of 5 mol L−1 (M) Li bis(fluorosulfonyl) imide (LiFSI) in a trimethyl phosphate (TMP) solvent. The concentrated 5 M LiFSI/TMP electrolyte showed good compatibility with graphite and no Al corrosion. More attractively, such a concentrated electrolyte can effectively suppress the growth of Li dendrites in Li metal batteries because of a stable LiF-rich SEI layer. Therefore, this highly concentrated electrolyte is promising for safe Li batteries.

Dong Yang, et al.^[3] applied LiFSI and LiBOB simultaneously in a 1mol / L LiPF6 / ethylene carbonate / diethyl carbonate electrolyte system to study the synergistic effect of the two on the electrolyte. Experimental results show that adding LiFSI to the electrolyte can significantly improve the cycle performance and rate performance of lithium-ion batteries. However, LitFSI is easy to corrode aluminum current collector. When LiBOB additive is added to the electrolyte system, it can effectively suppress the corrosion effect of LiFSI on aluminum foil. LiFSI can significantly reduce the high impedance of LiBOB. Therefore, LiFSI / LiBOB composite additives can significantly improve the rate performance and cycle performance of lithium ion batteries.

In the future, LiFSI will form a "gold partner" with more different lithium salts to help improve the overall performance of lithium-ion batteries.

Related links : LiFSI

References:

[1].Meng Li, Jingyi Qiu, Songtong Zhang,et al.The influence of new lithium salt lithium fluoride sulfonimide electrolyte on the performance of lithium ion batteries [J]. Energy storage science and technology,2017，6（1）：101-107.

[2].Pengcheng Shi, Hao Zheng, Xin Liang, Sheng Cheng, Chunhua, Chen, Hongfa Xiang.A highly concentrated phosphate-based electrolyte for high-safety rechargeable lithium batteries[J]. Chem. Commun., 2018, 54, 4453-4456, DOI: 10.1039/c8cc00994e